Installation structure of battery unit

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an installation structure of a battery unit enabling installation of a battery unit even in a vehicle, such as a three door-type vehicle, which has no luggage compartment. The present invention also relates to a setting structure of a seat for setting the rear seat to the floor of the vehicle without making a hole through the floor of the vehicle body.

2. Description of the Related Art

Conventional hybrid vehicles use a battery unit as an auxiliary driving power source in addition to a main driving power source. Since the battery unit used in a hybrid vehicle requires installation space, it is normally installed in the luggage compartment of the vehicle.

When the hybrid vehicle is provided with a luggage compartment, a part of the luggage compartment may be used for the battery unit. However, in three door-type hybrid vehicles, not provided with a luggage compartment, there is insufficient space for installing the battery unit. In addition, the portion of the vehicle body where the battery unit is installed is required to have a considerable degree of rigidity for supporting the battery unit, which is normally relatively heavy.

The present invention provides an installation structure of the battery unit even in a vehicle in which a luggage compartment is not provided.

The present invention also provides a setting structure of a seat for setting the rear seat to the floor of the vehicle without making a hole through the floor of the vehicle body so that the setting structure of the present invention is capable of preventing leakage of the gas through the vehicle body.

SUMMARY OF THE INVENTION

In order to solve the above problems, one embodiment of the present invention provides an installation structure for a capacitor as a battery unit providing auxiliary power for a fuel cell in a hybrid vehicle, even in a vehicle having no luggage compartment, in a standing state, the installation structure comprising a rear pillar cross member mounted behind a rear seat in the transverse direction of the vehicle and both ends of which are connected to inner panels and damper bases of wheel housing through respective brackets and reinforcing bracket plates, a floor cross member mounted on the upper surface of the rear floor of the vehicle in the transverse direction of the vehicle body wherein the top portion of said capacitor is joined to said rear pillar cross member and the bottom portion of said battery unit is joined to said floor cross member.

The above installation structure of the battery unit rigidly fixes the capacitor as the battery unit behind the rear seat in a standing state, leaving space for loading luggage since the top portion of the battery unit is supported by the inner panels of the wheel housing through the rear pillar cross member and the brackets, and the bottom portion of the battery unit is supported by the rear floor through the floor cross member. In addition, use of the inner panels serves to support the capacitor rigidly by distributing the load of the battery unit to inner panels on both sides, using the rear pillar cross member as a framework to connect both inner panels.

According to another embodiment of the present invention, a setting structure for a rear seat for reliably setting the rear seat on a rear floor without forming fitting holes through the rear floor of a hybrid vehicle, provided with a hydrogen tank under the rear floor, the installation structure comprising a floor front cross member mounted in the transverse direction of the vehicle on a front upper surface of the rear floor, comprising a setting seat for setting a front bottom of the rear seat and a front fixing hole, a floor rear cross member mounted in a transverse direction of the vehicle on a rear upper surface of a rear floor comprising a rear fixing hole, a rear seat body composing a step portion disposed at the front side bottom and a front fixing hole and a rear fixing hole for fixing the backside of the rear seat body, wherein the front side of the rear seat body is joined by engaging the step portion with backside of the front cross member and by fixing through the front fixing hole, and the rear bottom of the rear seat body is fixed with the backside of the floor rear cross member through the rear fixing hole.

The above setting structure for setting the rear seat by use of joining tools to these cross members, which are connected to the floor, makes it possible not to bore holes through the floor of the vehicle so that such setting prevents leakage of gas through the floor into the vehicle compartment. Moreover, since the cross members function as the members to stop the shift of the seat by engaging the bottom portion at the front side of the rear seat with the back wall of the front cross member, the above setting structure is quite stable against the forward load applied to the vehicle body when the vehicle is suddenly stopped.

According to the third aspect of the present invention, in an installation structure of the battery unit according to the first aspect, the bracket is connected to a damper base (for example, damper base <b>41</b> in the embodiment) of the wheel housing.

The above installation structure of the battery unit according to the third aspect of the present invention utilizes the increased rigidity of the damper base.

BRIEF DESCRIPTION OF THE DRAWING

<figref idref="DRAWINGS">FIG. 1</figref> is a side view of the installation structure of the battery unit explaining the present invention.

<figref idref="DRAWINGS">FIG. 2</figref> is a perspective diagram showing the front view of the installation structure of the battery unit of the present invention.

<figref idref="DRAWINGS">FIG. 3</figref> is a perspective diagram showing the rear view of the installation structure of the battery unit of the present invention.

<figref idref="DRAWINGS">FIG. 4</figref> is a perspective diagram of the main portion of the installation structure of the battery unit shown in <figref idref="DRAWINGS">FIG. 2</figref>.

<figref idref="DRAWINGS">FIG. 5</figref> is a cross-sectional diagram of the installation structure of the battery unit along A—A line of <figref idref="DRAWINGS">FIG. 2</figref>.

<figref idref="DRAWINGS">FIG. 6</figref> is a cross-sectional diagram of a seat fitting structure along C—C line of <figref idref="DRAWINGS">FIG. 9</figref>.

<figref idref="DRAWINGS">FIG. 7</figref> is a cross-sectional diagram of a seat fitting structure along B—B line of <figref idref="DRAWINGS">FIG. 9</figref>.

<figref idref="DRAWINGS">FIG. 8</figref> is a side view diagram showing the seat fitting structure of the present invention.

<figref idref="DRAWINGS">FIG. 9</figref> is a perspective diagram showing the front view of seat fitting structure of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the present invention is described below with reference to the attached drawings. The hybrid vehicle according to the present embodiment comprises a fuel cell (not shown) and a capacitor (battery unit) as an auxiliary electric source.

As shown in <figref idref="DRAWINGS">FIGS. 1 to 3</figref>, a front side of a rear floor <b>1</b> is formed to slope downwards in a stepwise manner. The leading edge of the rear floor <b>1</b> is joined to the trailing edge of the floor panel (not shown). The rear frame <b>2</b> is joined to the under surface of both side portions of the rear floor <b>1</b>, and the cross-sectional structural portion enclosed by the rear frame <b>2</b> and the rear floor <b>1</b> forms a framework K<b>1</b> of the vehicle body.

A cross member <b>4</b>, having an L-shaped cross-section, is joined upside of the rear frame <b>2</b> in the transverse direction of the vehicle to the rear surface of the step portion <b>3</b> in front of the rear floor <b>1</b>, and the cross-sectional structural portion enclosed by the cross member <b>4</b> and the rear floor <b>1</b> forms a framework K<b>2</b> of the vehicle body.

A reinforcing member <b>5</b>, which has an L shaped cross-section and which is formed by a plate thicker than the rear floor <b>1</b>, is joined by welding to the step portion <b>3</b> extending in the vehicle transverse direction upside of the rear frames <b>2</b>. The cross member <b>4</b> is reinforced by the reinforcing member <b>5</b>. A pair of two front fitting holes for fitting the front side of the rear seat <b>6</b> is provided on the upper surface of the reinforcing member <b>5</b>.

As shown in <figref idref="DRAWINGS">FIGS. 2 and 3</figref>, inner panels <b>9</b> of the wheel housing are joined, respectively, to flange portions <b>8</b> mounted on both sides of the rear floor <b>1</b>, and inner panels <b>9</b> together with outer panels (not shown) form wheel housings.

On the upper surface of the rear floor <b>1</b>, a floor cross member <b>10</b> having a U-shaped cross section is provided behind the reinforcing member <b>5</b> and in front of the inner panel <b>9</b> of the wheel housing, extending in the vehicle transverse direction upside of the installation position of the rear frame <b>2</b>. The floor cross member is formed to have a closed cross-section so as to provide advantageous structural strength to this member. On the upper surface of the floor cross member <b>10</b>, back mounting holes <b>11</b> for mounting the rear seat <b>6</b> are formed at positions corresponding to the front mounting holes <b>11</b>.

As shown in <figref idref="DRAWINGS">FIG. 1</figref>, a rear seat <b>6</b>, which is shown by dotted lines, is fixed to the front mounting holes <b>7</b> of the rear seat <b>6</b> provided on the reinforcing member <b>5</b> and to the back mounting holes <b>11</b> of the rear seat <b>6</b> provided on the floor cross member <b>10</b>. Two lower anchors <b>12</b> for fixing child seats (not shown) are provided on the floor cross member <b>10</b>. Note that each lower anchor <b>12</b> comprises an anchor bracket <b>12</b><i>a </i>to be joined to the floor cross member <b>10</b> and a ring member <b>12</b><i>b. </i>

A rear pillar cross member <b>14</b>, having a closed cross-section, is provided behind the rear seat <b>6</b>. This pillar cross member <b>14</b> is formed by jointing a front side member <b>15</b> and a rear side member <b>16</b>, both of which have L-shaped cross-sections with both ends of the pillar member formed so as to be inclined downward. Note that, as shown in <figref idref="DRAWINGS">FIG. 3</figref>, behind the rear pillar cross member <b>14</b>, upper anchors <b>21</b> and <b>21</b> are provided for fixing the child seat corresponding to the lower anchors <b>12</b> and <b>12</b>.

Each end of rear pillar cross member <b>14</b> is joined to an inner panel <b>40</b> of a rear fender by being supported through an upper support <b>38</b> and lower support <b>39</b>, which are shown in <figref idref="DRAWINGS">FIGS. 4 and 5</figref> described in a later section. The upper portion of the bracket <b>18</b> is fixed by bolts <b>17</b> to each edge portion of the rear pillar cross member <b>14</b> shrouding the upper support <b>38</b> and lower support <b>39</b>, and the lower portion of the bracket <b>18</b> is fixed to the damper base <b>41</b> of the wheel housing by bolts <b>20</b> through the reinforcing bracket plate <b>19</b>.

Assembling the rear pillar cross member <b>14</b>, inner panel <b>40</b> of the rear fender, and the damper base <b>41</b> of the wheel housing is described below in practical terms with reference to <figref idref="DRAWINGS">FIGS. 4 and 5</figref>.

As shown in <figref idref="DRAWINGS">FIGS. 4 and 5</figref>, the upper support <b>38</b> and the lower support <b>39</b> are located at the end of the rear pillar cross member. The outside of the upper support <b>38</b> is bent to form a flange portion <b>38</b><i>a</i>, and this flange portion <b>38</b><i>a </i>is used for jointing by welding to the inner panel <b>40</b> of the rear fender. A flange <b>39</b><i>a </i>is also formed at the outside of the lower support <b>39</b> and the flange <b>39</b><i>a </i>of the lower support is used for joining by welding to the inner panel of the rear fender.

In addition, the rear pillar cross member <b>14</b> and the upper support <b>38</b> are connected by fastening the bolt <b>38</b><i>c</i>, inserted through the fitting hole <b>22</b> located at the end of the rear pillar cross member <b>14</b>, by a weld nut <b>38</b><i>b </i>mounted at the rear surface of the upper support <b>38</b>. The rear pillar cross member <b>14</b> and the lower support <b>39</b> are also connected by fastening the bolt <b>39</b><i>c</i>, inserted through the fitting hole <b>42</b> located at the end of the rear pillar cross member <b>14</b>, by a weld nut <b>39</b><i>b </i>mounted at the front surface of the lower support <b>38</b>.

As shown in <figref idref="DRAWINGS">FIG. 5</figref>, a spring <b>43</b> for suspension is received in the inner panel <b>40</b> of the rear fender, a strut housing portion <b>44</b> connected to the rear floor <b>1</b> is formed, and the upper wall of the strut housing portion <b>44</b> forms the damper base <b>41</b>. Note that the damper base <b>41</b> also constitutes a part of the inner panel <b>9</b> of the wheel housing.

The upper portion of the bracket <b>18</b> is fixed by bolts <b>17</b> to the end portion of the rear pillar cross member <b>14</b> shrouding the upper support <b>38</b>. A reinforcing bracket plate <b>19</b> is mounted on the lower portion of the bracket <b>18</b> by bolts <b>20</b>, and the reinforcing bracket plate <b>19</b> is connected and fixed to the damper base <b>41</b> of the wheel housing. Note that bolts <b>17</b> and <b>20</b> in <figref idref="DRAWINGS">FIGS. 4 and 5</figref> indicate mounting locations of these bolts so that these numbers are enclosed in parentheses. In addition, T in <figref idref="DRAWINGS">FIG. 5</figref> indicates a tire of the vehicle.

The upper portion of the capacitor <b>23</b> is fixed to the rear surface of the rear pillar cross member <b>14</b> by fixing the upper fitting portions <b>24</b> of the capacitor by use of bolts <b>25</b>, and the lower portion of the capacitor is fixed on a pedestal <b>26</b>, connected with the backside of the floor cross member <b>10</b> and mounted on the rear floor <b>1</b>, by fixing the lower fitting portions <b>27</b> with bolts <b>28</b>, so that the capacitor <b>23</b> is thereby installed by the obliquely standing state inclining the upper potion of the capacitor in the backward direction. Thus, the capacitor <b>23</b> is placed behind the rear seat <b>6</b> so that the rear seat conceals the capacitor <b>23</b>.

The capacitor <b>23</b> is used for assisting the fuel cell by supplying auxiliary power when starting or accelerating using electrical energy that is stored in the capacitor <b>23</b> at the time of regenerative braking.

A rear side case <b>29</b> that houses the capacitor body (not shown) and the electrical equipment for the capacitor <b>23</b> and the front cover <b>30</b> that encapsulates the rear side case <b>29</b> are integrated with bolts to thereby form the capacitor <b>23</b>. The upper fitting portion <b>24</b> of the capacitor <b>23</b> comprises a fitting piece <b>24</b><i>a </i>of the rear side case <b>29</b> and a fitting piece <b>24</b><i>b </i>of the front cover <b>30</b>. Similarly, the lower fitting portion <b>27</b> comprises a fitting piece <b>27</b><i>a </i>of the rear side case <b>29</b> and the fitting piece <b>27</b><i>b </i>of the front case <b>30</b>. Note that the fitting pieces <b>27</b><i>a </i>and <b>27</b><i>b </i>are attached to the case <b>29</b> and the cover <b>30</b> by bolts <b>13</b>.

A suction portion <b>33</b> of a cooling wind duct <b>32</b> connected to the case <b>29</b> is provided above the capacitor <b>23</b>. On the other hand, below the capacitor <b>23</b>, an exhaust portion <b>34</b> of the duct <b>32</b> connected to the case <b>29</b> extends towards right, left, forward and backward directions. An exhaust port <b>35</b>, which opens upward, is provided together with a circulation fan at the end portion of the exhaust portion <b>34</b> for cooling the capacitor by circulating air through the duct <b>32</b> by circulating air. Note that the bracket <b>36</b> provided for setting the duct <b>32</b> is fixed to the bracket <b>37</b> provided at the rear floor <b>1</b> and the duct <b>32</b> is fixed to the rear floor <b>1</b>.

According to the above described embodiment, since the capacitor <b>23</b> can be supported by the floor cross member <b>10</b>, the rear pillar cross member <b>14</b>, bracket <b>18</b>, and the reinforcing bracket plate <b>19</b>, it is possible to reliably support the heavy and bulky capacitor <b>23</b>, even in the three door vehicle having no luggage compartment. In the present embodiment, since the capacitor <b>23</b> is installed behind the rear seat <b>6</b>, the capacitor <b>23</b> can be installed without sacrificing space of the compartment to ensure the luggage storage space at the rear portion and without affecting the exterior appearance of the vehicle.

Practically speaking, at the lower side of the capacitor <b>23</b>, the load of the capacitor <b>23</b> is transmitted through the four lower fitting portions <b>27</b> and the pedestal <b>26</b> to the floor cross member <b>10</b>, which is formed into a structure with a closed cross-section having advantageous strength, and the load is transferred from the floor cross member <b>10</b> and is distributed and supported by both left and right rear frames <b>2</b>, which form the framework K<b>1</b> of the vehicle body.

Since the load of the capacitor <b>23</b> applied to the floor cross member <b>10</b> is also transmitted through the rear seat <b>6</b> to the frontward reinforcing member <b>5</b>, the capacitor is also supported by the framework K<b>2</b>, which is formed by the cross member <b>4</b> under the reinforcing member <b>5</b> and the rear floor <b>1</b>. As a result, mainly the frameworks K<b>1</b> and K<b>2</b> extending in the longitudinal direction of the vehicle as well as the entire rear floor <b>1</b> support the load of the capacitor <b>23</b> so that quite reliable support of the capacitor <b>23</b> can be realized.

The load of the upper portion of the capacitor <b>23</b> is transmitted through the four upper fitting portions <b>24</b> to the rear pillar cross member <b>14</b>, and the load is transferred from both ends of the rear pillar cross member <b>14</b> through the bracket <b>18</b> and reinforcing bracket plate <b>14</b> to the inner panel <b>9</b> of the wheel housing, and the load is distributed and finally supported by the rear floor <b>1</b> and the rear frame <b>2</b>, which forms the framework K<b>1</b> of the vehicle body. Furthermore, the load applied to the rear pillar cross member <b>14</b> is transmitted through the upper support <b>38</b> and the lower support <b>39</b> to the inner panel <b>40</b> of the rear fender panel so that the capacitor <b>23</b> can be reliably supported.

Consequently, it is possible to increase the rigidity of the vehicle body by having the rear pillar cross member <b>14</b> function as the framework connecting the inner panels <b>40</b> of both right and left rear fenders, which form the side walls of the vehicle body, and therefore, the capacitor <b>23</b> is reliably supported by the inner panel by sharing the load with both inner panels <b>40</b>.

Since provision of the reinforcing bracket plate <b>19</b> and the bracket <b>18</b> enables an increase in the supporting rigidity of the damper base <b>41</b>, the spring force of the spring <b>43</b> used in the strut housing can be reduced by an amount corresponding to the increased amount of the supporting rigidity allowing the driver a more comfortable driving experience.

Since the frameworks K<b>1</b> and K<b>2</b> of the vehicle body reliably support the capacitor <b>23</b> located behind the rear seat <b>6</b>, the capacitor <b>23</b> can be situated in a vehicle having no luggage compartment while ensuring a high supporting rigidity.

Note that the present invention is not limited to the above-described embodiment, and the present invention can be applied not only to installation of the capacitor but also to installation of a battery. Furthermore, the floor cross member <b>10</b> can be favorably used as a mounting base for mounting a seat belt.

As described above, according to the first aspect of the invention, since the battery unit can be reliably supported in a vehicle body behind the rear seat while the load of the battery is distributed on the vehicle body, the battery unit can be reliably installed even in a vehicle having no luggage compartment.

According to the above installation structure, a comparatively large battery unit can be installed even in the vehicle having no luggage compartment by use of a rear pillar cross member, a floor cross member, and a bracket, without sacrificing the inside space of the vehicle and the space for storing luggage.

In the above construction, an effect of the present invention is obtained that the floor member can be used for a mounting member for mounting seats, seat belts, and child seat anchors.

According to the second aspect of the present invention, the functional use of the rear pillar cross member as the skeletal structure connecting the left and right inner panels, which constitute both side walls of the vehicle body, makes it possible to reinforce the vehicle body and to reliably support the battery unit while distributing the load of the battery unit to the inner panels.

According to the third aspect of the present invention, the bracket can improve the rigidity of the damper base for supporting the battery unit, so that the force of the spring can be reduced by an amount corresponding to the improved rigidity of the damper base, which results in improving driving comfort.

Hereinafter, “an installation structure of a seat”, which is disclosed in Japanese Patent Application No. 2002-101638 entitled “an installation structure of seat” filed on Apr. 3, 2002 is incorporated in the present specification as described below with reference to the above installation structure of the battery unit.

The hybrid vehicle of the present invention comprises a fuel cell (not shown) and the capacitor (battery unit), as described above. As shown in <figref idref="DRAWINGS">FIGS. 7 and 8</figref>, the cross-sectional structural portion surrounded by the rear floor <b>1</b> and the rear frame <b>2</b> constitutes the first framework of the vehicle body K<b>1</b> and the cross-sectional structural portion surrounded by the rear floor <b>1</b> and the cross member <b>4</b> constitutes the second framework K<b>2</b>.

As shown in <figref idref="DRAWINGS">FIGS. 6 and 7</figref>, at the step portion <b>3</b>, a reinforcing member <b>5</b>, which has an L-shaped cross-section and is made of a plate material thicker than that of the rear floor, is provided in the transverse direction of the vehicle above the setting portions of the rear frame <b>2</b> and the reinforcing member <b>5</b> is connected to the rear floor <b>1</b> by welding.

On the upper surface of the floor front cross member <b>10</b>, an upwardly inflated setting seat (upper base) <b>5</b><i>a </i>is provided for setting a seat body <b>6</b>A of the seat <b>6</b>, comprising a seat body <b>6</b>A and a seat back <b>6</b>B and two pairs of front fixing holes <b>2</b> for fastening the seat.

As shown in <figref idref="DRAWINGS">FIG. 6</figref> in detail, the floor front cross member <b>5</b> comprises a front wall portion <b>5</b><i>b </i>to be welded to the vertical wall <b>3</b><i>a </i>of the step portion <b>3</b>, and a back flange portion <b>5</b><i>c</i>, to be welded on the upper surface of the rear floor, so that the floor front cross member <b>5</b> constitutes a structure with a closed cross-section on the rear floor <b>1</b>.

As shown in <figref idref="DRAWINGS">FIGS. 8 and 9</figref>, inner panels <b>9</b> are joined by welding on both sides of the flange portion <b>8</b> of the rear floor <b>1</b> and the inner panel and the outer panel (not shown) form a wheel housing.

On the upper surface of the rear floor <b>1</b>, a floor rear cross member <b>10</b> having a U-shaped cross-section (cross member at the rear side) is provided in the transverse direction of the vehicle so as to ride the rear frame <b>2</b>. As shown in <figref idref="DRAWINGS">FIG. 7</figref> in detail, the front flange <b>10</b><i>a </i>and the back flange <b>10</b><i>b </i>of the floor rear cross member <b>10</b> are welded to the floor <b>1</b> and the floor rear cross member <b>10</b> so as to form a structure having a closed cross-section which is naturally strong. Backside fixing holes <b>11</b> for fixing the backside <b>6</b>A of the seat body <b>6</b> are provided at the upper wall of the floor rear cross member.

As shown in <figref idref="DRAWINGS">FIGS. 6 and 7</figref>, the rear seat body <b>6</b>A of the rear seat <b>6</b> is fixed by inserting a bolt <b>13</b> through the front fixing hole of the rear seat <b>6</b> of the floor front cross member <b>5</b> and the backside fixing hole <b>11</b> of the rear seat <b>6</b> of the floor rear cross member <b>10</b> from the rear sides of the floor front cross member <b>5</b> and the floor rear cross member <b>10</b> and by clamping the bolt <b>13</b> by a nut <b>15</b> located at the side of the rear seat body <b>6</b>A.

Note that, in the above case, fastening of the rear seat is carried out as shown above by inserting the bolt from rear sides of the floor front cross member <b>5</b> and the floor rear cross member <b>10</b> and by clamping the bolt using a nut disposed at the rear side of the rear seat, it is possible to fasten the rear seat using a nut at the rear side of the floor front cross member <b>5</b> and the floor rear cross member <b>10</b>.

As shown in <figref idref="DRAWINGS">FIG. 6</figref>, the bottom of the rear sheet body <b>6</b>A of the rear sheet <b>6</b> is formed by a thin flexible plate, and a recessed portion <b>6</b><i>a </i>is formed at the position above the front cross member <b>5</b>, and the step <b>6</b><i>b</i>, forming the back side wall of the recessed portion <b>6</b><i>a</i>, attaches to the back wall <b>5</b><i>d </i>of the floor front cross member <b>5</b> so as to resist to the load applied to the rear sheet due to the slip of the rear sheet when the brake is operated. Note that the floor rear cross member <b>10</b> is provided with two pairs of lower anchors <b>12</b> for fixing child seats (not shown) to respective rear seats <b>6</b>.

A rear pillar cross member <b>14</b> having a closed cross-section is provided in the transverse direction of the vehicle at the rear side of the rear seat <b>6</b>, and one end portion of the rear pillar cross member <b>14</b> is joined to the inner panel <b>9</b> in the wheel housing through the bracket <b>18</b> and the reinforcing bracket plate <b>19</b> and end portions of the rear pillar cross member <b>14</b> are also joined to the inner panel of the rear fender panel through a supporting member (not shown). As shown in <figref idref="DRAWINGS">FIG. 8</figref>, at the back side of the rear pillar cross member <b>14</b>, upper anchors for the child seats are provided at positions corresponding to the lower anchors <b>12</b>, <b>12</b> for the child seats.

The upper fixing portion <b>24</b> of the capacitor <b>23</b> is fixed at the rear side of the rear pillar cross member <b>14</b> and the lower fixing portion <b>27</b> of the capacitor <b>23</b> is fixed by bolts <b>28</b> on the pedestal <b>26</b>, which is joined to the back side of the floor rear cross member <b>10</b> and which is also fixed to the rear floor <b>1</b>, so that the capacitor <b>23</b> is fixed in a standing but slightly tilted position wherein the upper portion of the capacitor <b>23</b> is tilted backward.

A hydrogen tank <b>36</b> (fuel tank) is provided under the rear floor <b>1</b>, as shown in <figref idref="DRAWINGS">FIG. 6</figref>, and a fuel cell is provided under the front floor (not shown).

As described above, the rear seat body <b>6</b>A of the rear seat <b>6</b> is joined by means of bolts <b>13</b> and nuts <b>15</b> to the floor front cross member <b>5</b> and to the floor rear cross member <b>10</b>. Since it is not necessary to form a fitting hole in the rear floor <b>1</b> such that no counter measures are necessary to prevent exhaust gas from entering into the vehicle chamber, the present installation structure makes it possible to reduce the number of parts and to save assembly man-hours for assembly of the vehicle body. Furthermore, the present installation structure is capable of preventing the exhaust gas from entering into the vehicle chamber through the mounting holes of the rear seat. In addition, the present structure is also capable of improving the rigidity of the vehicle body since no mounting hole is formed in the floor plate and also due to the floor front cross member <b>5</b> and the rear floor cross member <b>10</b>.

The floor front cross member <b>5</b> and the floor rear cross member <b>10</b> not only function for supporting the rear seat, but also function as the stop member to stop the shift of the seat by engaging the step portion <b>6</b><i>b </i>disposed at the front bottom side of the rear seat <b>6</b> with the backside wall <b>5</b><i>d </i>of the floor front cross member when the seat is shifted toward the front, so that the seat is reliably fixed at a position resisting to the shifting force toward the front by the driver. Since the floor front cross member <b>5</b> and the floor rear cross member <b>10</b> are connected to the framework K<b>1</b> and are arranged along the framework K<b>2</b> of the vehicle body, the rear seat <b>6</b> can be supported by the entire structure of the vehicle body.

As described above, installation of the seat by use of jointing tools to these cross members, which are connected to the floor, makes it possible not to bore holes though the floor of the vehicle, so that such installation prevents leakage of gas through the vehicle body. Consequently, it is the first effect that measures to prevent gas leakage through the floor of the vehicle are not required and the man-hours for vehicle assembly can be reduced.

Moreover, since the cross members function as a member to stop the shift of the seat by engaging the bottom portion at the front side of the rear seat with the back wall of the front cross member, a second effect is that the vehicle framework is quite stable against the forward load applied to the vehicle body when the vehicle is suddenly stopped.